In a charged particle beam device such as a scanning electron microscope, a sample is irradiated with a charged particle beam, and secondary electrons, backscattered electrons, and the like emitted from the irradiation position are detected.
A secondary electron image formed by detecting the secondary electrons mainly has a surface profile contrast of the sample.
A backscattered electron image formed by detecting the backscattered electrons has a composition contrast in addition to the surface profile contrast.
In a conventional scanning electron microscope, in order to discriminate and detect secondary electrons and backscattered electrons, a trajectory of electron is deflected for discrimination and detection by an energy filter including a plurality of detectors and electrodes.
Patent Document 1 discloses an electron beam apparatus which uses: electrodes opposed to each other, between which a primary electron beam is positioned and an electric field is formed; and a magnetic pole (orthogonal electromagnetic field (EXB) apparatus) for forming a magnetic field which generates a deflection operation against a deflection operation of the electric field on the primary electron beam, to deflect secondary electrons and backscattered electrons at different angles, so as to separate the secondary electrons from the backscattered electrons for detection.
Patent Document 2 discloses an electron beam apparatus which uses a porous electrode which forms an electric field for energy filtering, to thereby discriminate between secondary electrons and backscattered electrons in terms of energy for detection.
Patent Document 3 discloses an electron beam apparatus which uses a secondary electron conversion electrode which generates secondary electrons by means of collision of backscattered electrons, to thereby detect the backscattered electrons or the secondary electrons with high efficiency.
According to the technologies disclosed in these Patent Documents, it becomes possible to separate secondary electrons and backscattered electrons on different trajectories for detection or detect the two types of electrons together, on the basis of a difference in energy.